I don't know about any medications for balance issues due to lesions. My balance issues are caused by a lesion in the cerebellum, which I think may be the case with many of us MSers, as well as muscle weakness. I will always have balance issues to varying degrees. I have attended PT in the past and am currently doing PT. I know that exercises can help but the symptoms can come and go depending on factors such as exacerbations, illnesses, stress, and heat to name a few. In the case of muscle weakness, exercise could exacerbate the balance issues.

I would recommend that she discuss it with her neuro. It could be unrelated to MS (like the B12 deficiency mrsD and Auntie Audrey suggested). I think finding out what is causing her balance issues would be first and treatment second.

Ampyra is helping me
 

My Neuro told me it only works in about 50% of people. I was one of the lucky ones it works for. I do notice fatigue and leg dragging when I forget to take a doze. You have to take it twice a day.

Some have been talking on a magnesium thread about balance improving when upping magnesium intake. My balance is so off since hip replacement and these days I take upwards of 1000mg magnesium divided thru the day. I do OK, but often in the house have caught myself from falling. I've been using higher doses of mag for years and experiment with many forms....glycinate, citrate, chloride, malate and I use a complex blend from life extension. There is info out there about mag deficiency and I'm sure it's rampant. Many take too much calcium and not enough magnesium...mag is necessary for our bones, some integrative people say more so than calcium. I take little calcium and don't use much dairy, some cheese.

The rheumy I was seeing for a couple years after hip surgery mess, tried to get me to take more calcium, but I didn't follow her advice. I've been studying this cal/mag ratio for many years. People do end up with calcium deposits in various places in body.

I use my Wii balance board and Wii Fit exercises for balance exercise. It's been recommended in the media also. It helps!

I use my wii too :p, nothing like getting exercise from video games, but even my neuro had recommended it since there's no YMCAs nearby to take advantage of their classes. Not only do I have tons of fun with the balance games, but the yoga is also supposed to be great, not as fun but fun enough to waste 15-20 mins a day playing.